Leade angle

[vegeta]

This whole thing about freebore has really gotten me confused. I have a JGS reamer that has 0.112 freebore but I am still able to load my Nosler ballistic tip 70 grain bullets out to touch the lands. I don't have a huge amount of bearing surface in the neck but it is not like the bullets are just barely in the neck. It still takes a lot of force to pull one of the bullets and I cannot move one by hand.

One thing I have noticed is that my reamer has a 3 degree leade angle. I have seen other specs where the leade angle is 1.5. Does this angle make a significant difference in the amount of freebore needed?

Thanks,

Bobby

 

[Cheechako]

Bobby

First of all, it's not leade angle, it's throat angle. The leade, or freebore, is the straight section directly in front of the case where the rifleing has been reamed away. Yes, throat angle does have an effect on seating depth. In the situation of long skinny VLD bullets it can make a big difference. Look at it this way. If there was no throat angle but instead a 90 degree transition from freebore to rifleing, the bullet would make contact at the point equal to the bore diameter. On the other hand, if the throat angle was very gradual, say 1/2 degree, the bullet would be seated out farther before it contacts the rifleing. Some benchrest rifles are chambered with a 1/2 degree angle. But that is usually compensated for by having a very short leade or freebore.

Ray

 

[MJC]

I have always said leade angle too. Looking at a reamer print it is indeed throat angle. I have also used the term throat dia. when referring to the leade/freebore dia. Everybody seemed to understand what I meant though. I guess I'll have to use the proper terminology from now on.